9415568 EGLINGTON This ancient, and potentially refractory material is particularly difficult to quantify, and represents an unknown ("hidden") component of the total organic carbon (TOC) in marine sediments. The reason for the paucity of information lies in the difficulty in making direct measurements of this elusive carbon pool. Kerogen, the dominant fraction of organic carbon in sedimentary rocks is difficult to characterize, being inert and lacking structural characteristicity. The PI proposes to use the fact that weathered carbon will, by definition, have an infinite radiocarbon age (i.e. "14C-dead") to determine its significance in marine sediments. Specifically, the PI will radiocarbon date individual sedimentary organic compounds in order to establish discrete ages for different OC pools. The overall objectives of the proposed project are to: 1.) Determine the age distribution of co-deposited sedimentary organic matter, 2.) Assess the proportion of weathered (14C-dead) organic carbon in recent marine sediments.